Impact of Four Plant Extracts on Bactrocera dorsalis a Pest on Fruits

Menthol extracts of four local plants (Ocimum tenuiflorum, Hibiscus, Mentha longifolia and Bougainvillea glabra) were analysed to check their toxicity on third instar larvae of B. dorsalis by estimating the larval mortality for four plant extracts and different times exposure (1-5 hr) and measured LT50 value for each plant extract. Larval mortality varies for extract of each studied plant as Ocimum tenuiflorum showed its highest value of 56.68% at 4.57hr, for hibiscus it was 72% at 3.5 hr., for Mentha longifolia it was 95.23% at 4 hr., while for Bougainvillea glabra it was 100% at 2 hr. exposure. The LT50 values for B. dorsalis varying from 1.011 for Bougainvillea glabra to 2.946 for Ocimum tenuiflorum whereas LT50 values were 1.402 and 1.123, forHibiscus and Mentha longifolia respectively. Present study results showed that Bougainvillea glabra was highly toxic whereas Ocimum tenuiflorum shows least toxicity.